package org.apache.maven.plugin.internal;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import java.util.Collection;
import java.util.IdentityHashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Map;

import org.apache.maven.artifact.Artifact;
import org.apache.maven.artifact.resolver.ResolutionListener;
import org.apache.maven.artifact.resolver.filter.ArtifactFilter;
import org.apache.maven.artifact.versioning.VersionRange;

/**
 * Assists in detecting wagon providers brought into the plugin class path via legacy Maven core
 * artifacts (e.g. maven-core:2.0.6) and excluding them. A plugin should be able to explicitly
 * declare dependencies on specific wagons for its use. However, the (old) wagons pulled in
 * transitively via legacy Maven core artifacts are usually not intended as dependencies and more
 * importantly screw up artifact resolution because they would get preferred over the core wagon
 * versions. This is a hack to provide backward-compat with Maven 2 (MNG-4528, MNG-4561).
 * 
 * @since 3.0
 * @author Benjamin Bentmann
 */
class PluginDependencyResolutionListener implements ResolutionListener {

  private ArtifactFilter coreFilter;

  private LinkedList<Artifact> coreArtifacts = new LinkedList<Artifact>();

  private Artifact wagonProvider;

  private Map<Artifact, Object> bannedArtifacts = new IdentityHashMap<Artifact, Object>();

  public PluginDependencyResolutionListener(ArtifactFilter coreFilter) {
    this.coreFilter = coreFilter;
  }

  public void removeBannedDependencies(Collection<Artifact> artifacts) {
    if (!bannedArtifacts.isEmpty() && artifacts != null) {
      for (Iterator<Artifact> it = artifacts.iterator(); it.hasNext();) {
        Artifact artifact = it.next();
        if (bannedArtifacts.containsKey(artifact)) {
          it.remove();
        }
      }
    }
  }

  public void startProcessChildren(Artifact artifact) {
    if (wagonProvider == null) {
      if (isLegacyCoreArtifact(artifact)) {
        coreArtifacts.addFirst(artifact);
      } else if (!coreArtifacts.isEmpty() && isWagonProvider(artifact)) {
        wagonProvider = artifact;
        bannedArtifacts.put(artifact, null);
      }
    }
  }

  private boolean isLegacyCoreArtifact(Artifact artifact) {
    String version = artifact.getVersion();
    return version != null && version.startsWith("2.") && !coreFilter.include(artifact);
  }

  public void endProcessChildren(Artifact artifact) {
    if (wagonProvider == artifact) {
      wagonProvider = null;
    } else if (coreArtifacts.peek() == artifact) {
      coreArtifacts.removeFirst();
    }
  }

  public void includeArtifact(Artifact artifact) {
    if (wagonProvider != null) {
      bannedArtifacts.put(artifact, null);
    }
  }

  private boolean isWagonProvider(Artifact artifact) {
    if ("org.apache.maven.wagon".equals(artifact.getGroupId())) {
      return artifact.getArtifactId().startsWith("wagon-");
    }
    return false;
  }

  public void manageArtifact(Artifact artifact, Artifact replacement) {
  }

  public void omitForCycle(Artifact artifact) {
  }

  public void omitForNearer(Artifact omitted, Artifact kept) {
  }

  public void restrictRange(Artifact artifact, Artifact replacement, VersionRange newRange) {
  }

  public void selectVersionFromRange(Artifact artifact) {
  }

  public void testArtifact(Artifact node) {
  }

  public void updateScope(Artifact artifact, String scope) {
  }

  public void updateScopeCurrentPom(Artifact artifact, String ignoredScope) {
  }

}
